The invention relates to a window wiper device for a vehicle, in particular a motor vehicle, and furthermore in particular a wiper lip for a window wiper device.
Window wiper devices typically have a wiper arm or wiper lever, wherein a wiper blade to which a wiper lip is fastened is moved on the window of a motor vehicle. The wiper arm is moved in alternating fashion between a first turning point and a second turning point. For this purpose, the wiper arm is connected by way of the drive shaft to a wiper motor. In particular on windshields with intense changes in curvature, the wiper blade with the wiper lip easily loses contact with the window. This can give rise, in particular in the case of intensely curved windows, to non-wiped wiping areas and/or to smearing.
In the case of window wiper devices known from the prior art, a noise is commonly generated upon the reversal of the wiper arm at the turning points, which noise is, in particular depending on the motor vehicle and/or a driving situation of the motor vehicle, perceived as disturbing. Said noise is caused in particular by the fact that, during a reversal of the movement direction of the wiper arm or of the wiper blade, the wiper lip is initially turned upright, wherein the wiper arm is forced away from the window, and subsequently folds over in the respective other direction. During the folding-over, the wiper arm together with the wiper blade is accelerated in the direction of the window. Here, the wiper blade moves in the direction of the window and is then abruptly braked. As a result of the acceleration and the braking, an impact against the window occurs, which generates the noise. It is therefore sought to further improve window wiper devices, in particular to prevent or at least reduce noises of the window wiper device.
Furthermore, the wiping movement can lead to torsion of the wiper arm, that is to say to torsion about an axis which substantially corresponds to the longitudinal extent of the wiper arm or wiper blade. Such torsion may even, in the case of conventional window wiper devices, lead to contact between the wiper arm and a window. It is therefore also sought to reduce the torsion of the wiper arm.
In improving window wiper devices, there are numerous boundary conditions that should be taken into consideration. These include the outlay for production or the production costs, the material costs, and also the characteristics of the window wiper device, in particular the function under a variety of conditions and the durability under a multiplicity of conditions. Here, in the case of wiper devices for vehicles, it must be taken into consideration that the cost pressure is ever-increasing, and that vehicles may be used in a multiplicity of climatic conditions, such that, for example, extreme temperature values are encountered permanently and/or with great fluctuations.